| dc.description.abstract | Lining with shotcrete was tested in road tunnels in the early 1960's. The experience gained was so unsatisfactory that the support method was hardly used in road tunnels for almost 15 years. The main reason for this were problems with delamination, water leakage, frost damage as well as diffculties in assessing safety and the demand for maintence. To evaluate the performance of different support methods, 140 road tunnels have been studied, of which 32 had shotcrete linings. The linings amount totally to an area of 186'274 m2. Half of this, 90'862 m2, was so penetrated by water leaks that water and frost protective panels were, or should have been installed. The total shotcreted area penetrated by water is probably much higher since large areas were already covered by panels when mapped. | no_NO |
